(a) Field of the Invention
The present invention relates to a method of manufacturing an organic light emitting diode (“OLED”).
(b) Description of the Related Art
As display devices have become larger, flat panel display devices that occupy small spaces become increasingly required. In particular, an organic light emitting diode (“OLED”) display has been rapidly developed as one of the flat panel display devices.
An internal quantum efficiency of an OLED depends on the charge balance factor, the efficiency of production for singlet excitons, and the quantum efficiency of fluorescence. The efficiency of the OLED can be improved by adjusting one of the above-described terms For example, the charge balance factor such as injection and transport of electrons and holes related to the charge balance factor may bee adjusted.
In a π-conjugated compound, since hole mobility is tens to hundreds of times larger than electron mobility, the adjustment of the injection and the transport of holes may be sufficient to improve the efficiency of the OLED.
For adjusting the injection of holes, it is suggested that the surface of an anode made of indium tin oxide (“ITO”) may be treated with an acid or a base, or a thin film of CuPc, ZnO, NiO, etc., may be inserted between an anode and a hole transport layer.
However, these methods need complicated processes and increase a driving voltage of the OLED.
In particular, the insertion of a sputtered NiO thin film causes manufacturing processes to become complicated, thereby increasing manufacturing time.